Petri dishes are known in the art, the first petri dish having been invented by the German bacteriologist Mr. Julius Richard Petri in 1877. In general, the petri dish is a shallow glass or plastic cylindrical dish that biologist use to culture microbes. Usually, the petri dish is partially filled with warm liquid agar along with a particular mix of nutrients, salts and amino acids, and optionally, antibiotics, that match the metabolic needs of the microbe being studied. After the agar solidifies, the petri dish is ready to receive the microbe to be studied.
When a petri dish is being used, i.e., when it contains an active tissue culture, it is often stored in an incubator with other petri dishes. Typically, due to space limitations within the incubator, the petri dishes are stacked. In a typical laboratory environment, the applicable air filters are installed or connected to the incubator or other holding unit that contains multiple petri dishes, each of which can be contaminated if the air within the holding unit is contaminated. Controlling contamination within the significantly larger holding unit is potentially compromised whenever the holding unit is opened to access any of the multiple petri dishes in the holding unit. Under typical laboratory conditions, users access the holding unit a number of times in a specified time period. For example, if there are 30 petri dishes in a holding unit, a laboratory technician may open the holding unit each time he or she needs to access a single petri dish, exposing the air in the holding unit to the large air volume in the room outside the holding unit. Even though the holding unit may itself be filtered, each time the unit is opened, the elements in the air within the unit are potentially compromised by the room air. Although the holding unit ultimately then filters the new room air, during the time it takes the unit to re-filter the air, the culture in the petri dish is exposed to a less than optimal environment. The petri dish needs access to air and obtains such air in the space(s) where the top and bottom of the petri dish, or other pieces of the dish, come together when the dish is closed. By using a filtered petri dish, the possibility of contamination is limited to the times when the specific petri dish is opened to access its contents. The inventor of the present invention has achieved significantly greater productivity with the filtered petri dish design. Therefore, there is clearly a need for a petri dish having a filter incorporated therein for filtering air entering the petri dish.